Automatic plate exchanger for printing machines



P. FISCHETTI 2,990,768

AUTOMATIC PLATE EXCHANGER FOR PRINTING MACHINES July 4, 1961 Filed Jan. 31, 1958 m m M PASQ UALE FISCHETT/ ATTORNEY United States Patent 2,990,768 AUTOMATIC PLATE EXCHANGER FOR PRINTING MACHINES Pasquale Fischetti, Englewood, NJ., assign'or to Davidson Corporation, a corporation of New York Filed Jan. 31, 1958, Ser. No. 712,429 2 Claims. (Cl. 101217) This invention relates to control means for short run duplicators, such as the duplicator which is the subject of U.S. Patent 2,759,416; and more particularly to means for controlling the attachment of printing plates to and their subsequent removal from the printing cylinder of such a machine.

In short run duplication work, generally only a small number of printed copies are reproduced from each printing plate. However, during the course of a day, it may be desired to reproduce copies from a large number of different plates, thus requiring frequent interchanging of plates. In order to minimize the non-productive time during which plates are changed, it is desirable to effect the change of plates automatically without the necessity of arresting the motion of the printing cylinders.

For this reason, it is advantageous to equip machines of the type described in the abovementioned patent with cam operated plate grippers, such as the gripper described in copending application, Serial No. 693,207, now Patent No. 2,935,937. The operating cams for such a gripper must, of course, normally be disposed out of gripper activating position, to prevent opening 'of the gripper with every rotation of the machine. It is only when an expended plate on the printing cylinder is to be removed therefrom and a fresh plate attached thereto that the op erator should shift the cams to a position in which they will activate the gripper.

Although the cam control means employed heretofore has proven generally satisfactory, inasmuch as the peo ple who use these machines are not highly skilled in the operation thereof, it is desirable to make the control of such a machine as simple as possible. Toward this end, the present invention provides a plate gripper cam control means whereby an operator may change printing plates on the printing cylinder easily and without exercise of skill.

The invention will now be more fully described with reference to the accompanying drawings, in which:

FIG. 1 is a side elevational view of a short run duplicator showing the control handle and associated linkages of the present invention;

FIG. 2 is an oblique cross-sectional view taken on line 22 of FIG. 1;

FIG. 3 is a horizontal cross-sectional view taken on line 3-3 of FIG. 1; and

FIG. 4 is an oblique'face view showing the faceplate through which the control handle projects.

Referring to the drawings, azshort run duplicator 10, is represented in FIG. 1. As usual aplate-platen cylinder 11 and a blanket cylinder 12 are mounted on shafts 13 and 14 respectively, both shafts being rotatably jou-rnalled adjacent their ends in the side frames of the machine 10, one of which is side frame 15. The mechanisms shown in solid lines in FIG. 1 are disposed on the outward side of the machine frame 15. The equipment shown in dotted lines is on the inward side of the machine frame.

A handle 16, projecting through a faceplate 19, FIG. 4, past the upper edge of side frame 15, is the control member of the present invention. The control handle 16, as

shown in solid lines, is in itsneutral position, while its two operating positions are shown in dot-and-dash lines. The handle is pivotally mounted at 20, and is provided,

near its lower end, with a roller 21, rotatably mounted thereon. A tension spring 22, disposed between the lower 2 end of the handle 16 anda pin 23 fastened to the machine frame, maintains the handle in neutral position, when the handle is'not in operation. When the handle has been moved to. either of the two operating positions, spring 22 returns it to neutral position as soon as the operator releases the handle. 9

As was mentioned before, the control handle -16 has two operating positions. One 16a, is used to remove a printing plate presently secured to the printing cylinder, the other 1612 is the position .used when securing a new plate to the printing cylinder. The mechanism associated with the handle 16 for removing a plate secured to the printing cylinder comprises a lever 24, pivotally mounted at 25, and an activating arm 26, fixedly mounted on lever 24, and pivoted about pin 25 forming a bell crank arrangement with the lever 24. The lower edge of lever 24 is notched at 29 near one end, and the lever contacts roller 21 near its other end. Notch 29 is positioned for engagement with pin 30 whenever handle 16 is in plate removing position 16a, for a purpose which will be described hereinafter. A tension spring 31 disposed between the lower portion of arm 26 and pin 32 fastened to the machine frame, biases the arm in a clockwise direction, and thereby urges lever 24 into contact with roller 21. As can be seen in 'FIG. 3, the lower end of activating arm 26 is provided with a beveled cam surface 33, whose purpose will be described below.

The direct end achieved by shifting handle 16 into either of its operating positions, is to move one or the other of two cams 34 or 35 into positions wherein the cams will actuate a cam operated plate gripper, mounted in cylinder 11. The cam 34 which serves to open the plate gripper for removal of a printing plate is shown in FIG. 3. The follower roller 36 and a portion of the crank arm 39 of a cam operated gripper are indicated as well, rotating in the direction shown. It is apparent that at the present time, cam 34 is not in the path of follower roller 36 hence the gripper will not be actuated. In order to activate the gripper, cam 34 must be translated from the position shown in solid lines, to the dot-anddash position, which is in the path of follower roller 36. For this reason, cam 34 is provided with two short rods 40 and 41, projecting perpendicularly from the frameward side of the cams, which slidably pass through two apertures in the side frame 15. The short rods are fastened to the flange 42 of a cam block 43, by nuts 44 and 45. The cam block 43, is furnished with a beveled cam surface 46 which cor-responds to the beveled cam surface 33 of activating arm 26. A compression spring 49 arranged between the side frame 15 and cam block 4 3 in two aligned wells, serves to maintain cam 34 in its normal, out of operation position.

When it is desired to move cam 34 into operating position, i.e. when a printing plate fastened to the printing cylinder is to be removed therefrom, handle 16 is shifted into position 16a, thereby pivoting lever 24, and hence arm 26, in a counterclockwise direction, whereupon the lower portion of arm 26 is transferred toward the right, as indicated in FIG. 3, resulting in the engagement of cam surface 33 of arm 26 with cam surface 46 of cam block 43. Continued movement of activating arm 26 naturally results in the translation of cam '34 into the path of roller 36, against the force of spring 49.

As was mentioned before, the lower edge of lever 24 is notched adjacent one end of the lever, the notch 29 arranged to engage a pin 30 when handle 16 is in position 16a. The pin 30 is mounted on a lever 50, which is pivotally mounted on the machine frame 'at 51. The pin projects inwardly from the lever through an aperture in side frame 15, and is disposed beneath a pivotally mounted bracket 47 which holds a seriesof stripper rollers 48. The purpose of the rollers 48 is to cooperate with cylinder 11 to drive printed sheets into the delivery mechanism after the sheet has been released by the paper gripper. It is undesirable however, to have the rollers 48 contact the plate half of the cylinder, since theimage on the plate might thereby be smudged. It is therefore the duty of the cam operated lever 50, and associated pin 30 to lift the bracket 47 and hence raise the rollers 48 off cylinder 11 during approximately one-half of each cycle when the plate is passing beneath the position of the rollers.

When a run has been completed and a printing plate is to be removed, handle 16 is placed in position 16a and the plate is released from the gripper as described above. Since the expended printing plate is to be handled by the same delivery mechanism which handles the printed sheets, it is desirable that during this one cycle in which the plate is being removed and delivered, that the rollers 48 contact the printing plate to aid in the delivery. The purpose of notch 29 engaging pin 30 when a plate is being removed is therefore, to prevent the pin from raising the rollers off cylinder 11 when the plate segment of the cylinder passes thereunder.

The mechanism, associated with handle 16, which is employed when attaching a new printing plate to the printing cylinder comprises a rod 52, which is bent in several directions, and a bell crank 53, pivotally mounted at 54 on a bracket 55 which is fastened to the side frame 15, see FIG. 2. One end of rod 52 is fastened to handle 16 at a point intermediate its ends, and the other end is fas' tened to one arm of the bell crank 53.

Cam 35 is utilized to open the aforementioned plate gripper when it is desired to secure a new printing plate on cylinder 11. As was described with reference to cam 34, cam 35 must be translated from the position shown in solid lines to that shown in dot-and-dash lines, the latter being disposed in the path of follower roller 36, in order to actuate the plate gripper. To accomplish this end, the cam construction of FIG. 2 is similar to that of FIG. 3. Cam 35 is provided with two short rods 55 and 56, projecting perpendicularly from the frameward side of the cam, which slidably pass through two apertures in the side frame 15. The short rods are fastened to the flange 59 of a flanged block 60, by nuts 61 and 62. A compression spring 63 arranged between the side frame 15 and flanged block 60 in two aligned wells, serves to maintain cam 35 in its normal, out of operation position.

When the plate gripper is to be opened to allow insertion of a printing plate therein, handle 16 is shifted into position 16b. The rod 52 is thereby moved downwardly, as indicated in FIG. 2, thus serving to pivot the bell crank 53 in a clockwise direction, bringing the free arm of the bell crank, which is normally disposed directly in front of the flanged block 60, into contact with the head of the flanged block. The continued clockwise movement of the bell crank 53 serves to translate cam 35 from its solid line position to the dot-and-dash line position, which is in the path of roller 36, against the force of spring 63.

In these machines, both printing plates and paper stock are fed into their respective grippers by the same feeding mechanism. The usual stop fingers and feed rollers, which are a part of the feeding mechanism, are normally activated in timed relationship with the appearance of the paper gripper at the feed side of the machine, which is the right side in FIG. 1. However, when a printing plate is being fed, the timing of the operation of the stop fingers and feed rollers must be changed by a 180 rotation of the printing cylinder 11, in order that they be activated in accordance with the appearance of the plate gripper at the feed side of the machine. This change in timing is ordinarily accomplished by employment of mechanism shown in FIG. 1.

The timing above referred to is controlled by a generally circular cam 64, mounted on the end of plate-platen cylinder shaft 13, having a depression in its periphery, the purpose of which will be described below. A lever 65, pivotally mounted at 66, carries a follower roller 69, adjacent one end, which is biased into contact with the cam 64 by a tension spring 70, disposed between lever 65 and side frame 15. It is through lever 65 that the timing of cam 64 is transmitted to the feeding mechanism for periodic feeding of paper stock.

Another lever 71, pivotally mounted at 72, carries a follower roller 73, intermediate its ends, which is biased into engagement with cam 64, at a point from roller 69, by a tension spring 74, disposed between the lever 71 and the side frame 15. An arm 75, pivotally mounted at 76, has a link 79 pinned thereto, intermediate its ends, the link 79 being free to pivot about pin 80. Link 79 is provided with two notches 81 and 82 which are arranged to accommodate two pins 83 and 84 respectively, pin 83 being fastened to lever 65 and pin 84 being fastened to lever 71. The mechanism is so constructed, that both pins may not be accommodated in their respective notches in link 79 at the same time.

A tension spring 85, disposed between link 79 and arm 75 normally maintains the mechanism in the position shown in FIG. 1. This is the paper stock feeding position. A rod 86 pivotally mounted adjacent the free end of arm 75 is fastened at its other end to a lever 89, which is mounted adjacent the end of a pivotal or rock shaft 90, on which are mounted the abovementioned stop fingers. Lever 89 in turn operates a crank arm 91 which is mounted on a pivotal shaft 92 which carries the aforementioned upper feed roller. This feed roller is normally out of contact with the lower feed roller.

When paper is being fed to the machine, the mechanism is arranged as shown in FIG. 1. Roller 69 enters the depression on the surface of cam 64 when the paper gripper comes around to the feed side of the machine, causing lever 65 to pivot clockwise, thereby moving rod 86 in the direction shown in FIG. 1. Rod 86 pivots lever 89, which serves to pivot the stop fingers, mounted on shaft 90, out of the path of the sheet of paper stock, and lever 89 in turn pivots the crank arm 91, serving to bring the upper feed roller, mounted on shaft 92, into contact with the lower feed roller for driving the sheet into the paper gripper.

When a printing plate is to be fed, handle 16 is moved to position 16b. Roller 21 pivots link 79 in a counterclockwise direction, thereby engaging notch 82 with pin 84 and disengaging notch '81 and pin 83. The stop fingers and feed rollers will now be operated in exactly the same way as before when roller 73 enters the depression in cam 64. In other words, the feed rollers and stop fingers will be operated when the plate gripper comes around to the feed side of the machine.

Assuming that a printing plate, which it is desired to replace, is presently secured on the printing cylinder, the invention operates in the following manner. Handle 16 is shifted into position 16a. Cam 34 is thereby moved into the path of plate gripper follower roller 36, in the manner described above. When roller 36 strikes cam 34, the plate gripper opens, ejects the expended plate therefrom, and the plate is thereupon delivered to a delivery basket. The handle 16 is then moved to position 16b, as a new plate is fed to the stop fingers of the duplicator. Cam 35 is moved into the path of follower roller 36, serving to open the plate gripper at the same time that the stop fingers and feed rollers are activated, resulting in the insertion of the new plate into the gripper.

This invention then provides an extraordinarily simple control means whereby an unskilled operator will have no trouble attaching printing plates to, or removing such plates from, a printing cylinder.

Having thus described the present invention, it is realized that many apparently different embodiments can be made without departing from the spirit and scope thereof and therefore the description and drawings hereof are to be interpreted in an illustrative rather than a limiting sense.

What is claimed is:

1. A rotary printing press wherein printing plates are gripped by a plate gripper mounted on the plate cylinder and automatically exchanged while said plate cylinder continues to rotate and having a first cam slideable between gripper operating and inoperative positions but normally spring-biased to the inoperative position, said first cam being adapted to open and close said plate gripper to effect the detachment of a plate from the plate cylinder, a second carn slideable between gripper operating and inoperative positions normally spring biased to the inoperative position, said second cam being adapted to open and close said plate gripper to efiect the attachment of a plate to said plate cylinder, said press comprising a single control handle for controlling the detachment and attachment of printing plates from and to the plate cylinder, said handle being movable to plate detach and plate attach positions, means operative when said handle is moved to plate detach position to slide said first cam into gripper operating position, and additional means operative when said handle is moved to plate attach position to slide said second cam into gripper operating position.

2. A rotary printing press according to claim 1 wherein said operative means includes a lever, an arm connected thereto, said arm acting to slide the first cam into operative position when the handle is moved to plate detach position to engage said lever, and said additional operative means includes a link connected to said handle for sliding the second cam into operative position when the 10 handle is moved to plate attach position.

References Cited in the file of this patent UNITED STATES PATENTS 2,117,165 Hernlund May 10, 1938 15 2,380,744 Ford July 31, 1945 2,482,408 -Ford Sept. 20, 1949 2,573,810 Runblad Nov. 6, 1951 2,766,689 Kow-alsky et a1. Oct. 16, 1956 2,821,910 Mazzio et all. Feb. 4, 1958 20 2,830,534 Springer et a1. Apr. 15, 1958 

